Premium
Molecular basis for the spontaneous generation of colonization‐defective mutants of Streptococcus mutans
Author(s) -
Ueda S.,
Kuramitsu H. K.
Publication year - 1988
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1988.tb00014.x
Subject(s) - biology , glucosyltransferase , mutant , streptococcus mutans , homologous recombination , gene , escherichia coli , microbiology and biotechnology , southern blot , dna , genetics , colonization , bacteria
Summary Spontaneous mutants of Streptococcus mutans GS‐5 defective in sucrose‐dependent colonization of smooth surfaces are generated at frequencies above the spontaneous mutation rate. Southern blot analysis of such mutants suggested rearrangement of the genes coding for glucosyltransferase (GTF) activity. Two strain GS‐5 homologous tandem genes, gtfB and gtfC , coding for GTF‐I and GTF‐S activities respectively, were demonstrated to undergo recombination when introduced into recombination‐proficient Escherichia coli transformants. However, the two genes were quite stable when transformed on a single DNA fragment into a recA mutant of E. coli. The DNA fragment coding for GTF activity from one S. mutans colonization‐defective mutant, SP2, was isolated and shown also to have undergone recombination between the gtfB and gtfC genes, resulting in reduced GTF activity. These results are discussed relative to the in vivo generation of colonization‐defective mutants in cultures of S. mutans.